Various kinds of farm implements are towed behind a tractor and include equipment operated by a driveshaft connected to the power takeoff (PTO) of the tractor. Agricultural sprayers are one example of such farm implements. Agricultural sprayers typically include a pump driven by the PTO, and power from that shaft may also operate agitator paddles contained in the tank of the sprayer and fans that blow the spray toward trees or other intended targets.
The conventional tractor-drawn sprayer or other PTO-powered equipment is hitched to the drawbar of the tractor with a clevis or similar attachment allowing pivotable movement between the tractor and the towed equipment. To accommodate pivoting movement between the tractor and the towed equipment in the drive train extending rearwardly from the PTO, a constant velocity (CV) joint conventionally is attached to the PTO shaft at the back of the tractor, and a drive shaft extends rearwardly from the CV joint to connect with a driven shaft at the front end of the equipment. The CV joint maintains a constant instantaneous rotational velocity of the drive shaft, throughout each complete revolution of the PTO shaft, whether or not the tractor is turning relative to the towed equipment. The CV joint ideally should be located in vertical alignment with the pivot point at which the towed equipment attaches to the drawbar of the tractor, so that turning movement of the CV joint occurs along a vertical axis coinciding with the turning axis of the hitch. However, in practical applications, such vertical alignment of the CV joint with the hitch is not always present. If the CV joint becomes misaligned with the pivot point of the hitch, oscillating linear forces are produced that apply undesirable thrust loads to the rotating CV joint as the tractor turns.
Furthermore, because the conventional drawbar-mounted pivot point is located close to the rear axle of the tractor, the towed equipment does not closely track the path of the tractor during turns. This lack of tracking increases the likelihood that the tractor driver towing a grove sprayer, for example, may turn too sharply at the end of a row, sideswiping a tree with the sprayer and damaging the tree or the sprayer.